Abstract Evaluating policies for improving surgical care in the elderly The 2010 Affordable Care Act (ACA) dramatically accelerated the pace of adoption for new policies aimed at reducing costs and improving quality. The ACA included several mandates to pilot test or scale up existing payment reforms that incentivized improved care for Medicare patients. The extent to which these policies will be effective at improving outcomes and reducing costs in surgery is unknown, however. Although some of these policies were previously implemented as Medicare Pilot programs, many are in their early stages and have not been rigorously evaluated. Because these efforts by CMS have substantial programmatic and opportunity costs, understanding their effectiveness and comparative value is essential. We therefore propose a systematic evaluation of the impact of these policy options on the quality and cost of surgical care in the national Medicare population. With these goals in mind, our current proposal has the following aims: Aim 1. To evaluate the impact of CMS improvement policies on surgical outcomes. We will conduct evaluations of three new policy strategies (non-payment for adverse events, bundled payments, and accountable care organizations) in the national Medicare population undergoing inpatient surgery. For each policy approach, we will take advantage of a natural experiment (i.e., a specific program or policy implemented that was recently implemented). Aim 2. To evaluate the impact of CMS improvement policies on Medicare payments around the surgical episode. For these same policies, we will evaluate their impact on price-standardized Medicare payments for the full range of services around surgical episodes. Using previously defined episodes of care for surgery, we will study the impact of these policies on Medicare payments that can be linked to complications and poor quality care, including payments for the index hospitalization, physician services, readmissions, and post-acute care. Aim 3. To evaluate the unintended consequences of CMS improvement policies on vulnerable Medicare patients. We will assess whether these policies resulted in unintended harm within those hospitals that serve vulnerable Medicare populations (e.g., hospitals serving a disproportionate share of minorities and/or low income beneficiaries). We will assess the degree to which Medicare payment penalties (or rewards) from these policies vary across hospitals serving vulnerable (vs. less vulnerable) populations. Results from this study have the most immediate impact on CMS policymakers. These results will facilitate evidence-based policymaking by providing data on the comparative effectiveness of these policy options.